Well Secret Argent Man, on the bright-side => I'm sure that if he collects coins, he's still gonna want to talk about coins ... but while you're talking about coins next Christmas, merely mention/gently-warn-him that you've heard that cleaning coins "may" reduce the coins value, and then leave it at that ... you can still talk about coins (just don't let that mutha get hold of your coins!)
... yes, talking about coins is always cool ..
